Approaches for providing target values to improve usefulness of external quality assessment scheme the Spanish experience

1993 ◽  
Vol 53 ◽  
pp. 19-27
Author(s):  
C. Ricos ◽  
V. Alvarez ◽  
A. Hernández ◽  
C. V. Jimenez ◽  
J. Minchinela ◽  
...  
Keyword(s):  
Quality Assessment ◽  
External Quality Assessment ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
Target Values

Establishing an Accuracy Basis for the Vitamin D External Quality Assessment Scheme (DEQAS)

2017 ◽  
Vol 100 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
Carolyn Q Burdette ◽  
Johanna E Camara ◽  
Federica Nalin ◽  
Jeanita Pritchett ◽  
Lane C Sander ◽  
...  
Keyword(s):  
Vitamin D ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
Measurement Procedure ◽  
Binding Assays ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
Hydroxyvitamin D ◽  
Target Values ◽  
High Concentrations

Abstract Until recently, the Vitamin D External Quality Assessment Scheme (DEQAS) assessed the performance of various assays for the determination of serum total 25-hydroxyvitamin D [25(OH)D] by using a consensus mean based on the all-laboratory trimmed mean (ALTM) of the approximately 1000 participants' results. Since October 2012, the National Institute of Standardsand Technology (NIST), as part of the Vitamin D Standardization Program, has participated in DEQAS by analyzing the quarterly serum sample sets using an isotope dilution LC-tandem MS (ID LC-MS/MS) reference measurement procedure to assign an accuracy-based target value for serum total 25(OH)D. NIST has analyzed90 DEQAS samples (18 exercises × 5 samples/exercise) to assign target values. The NIST-assigned values are compared with the ALTM and the biases assessed for various assays used by the participants, e.g., LC-MS/MS, HPLC, and several ligand-binding assays. The NIST-value assignment process and the resultsof the analyses of the 90 DEQAS samples are summarized. The absolute mean bias between the NIST-assignedvalues and the ALTM was 5.6%, with 10% of the samples having biases >10%. Benefits of the accuracy-based target values are presented, including for sample sets with high concentrations of 25(OH)D2 and 3-epi-25(OH)D3.

Evaluation of the ARKRAY HA-8190V instrument for HbA1c

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Eline A.E. van der Hagen ◽  
Sanne Leppink ◽  
Karin Bokkers ◽  
Carla Siebelder ◽  
Cas W. Weykamp
Keyword(s):  
Quality Assessment ◽  
Concentration Level ◽  
External Quality Assessment ◽  
Clinical Samples ◽  
Diabetic Patients ◽  
External Quality ◽  
Target Values ◽  
Performance Specifications ◽  
Certification Programme ◽  
And Performance

Abstract Objectives Hemoglobin A1c (HbA1c) is a valuable parameter in the monitoring of diabetic patients and increasingly in diagnosis of diabetes. Manufacturers continuously optimize instruments, currently the main focus is to achieve faster turnaround times. It is important that performance specifications remain of high enough standard, which is evaluated in this study for the new ARKRAY HA-8190V instrument. Methods The Clinical and Laboratory Standards Institute (CLSI) protocols EP-5, EP-9 and EP-10 were applied to investigate imprecision, bias and linearity. In addition potential interferences, performance in External Quality Assessment (EQA) and performance against the HA-8180V instrument in 220 clinical samples was evaluated. Results The HA-8190V demonstrates a CV of ≤0.8% in IFCC SI units (≤0.6% National Glycohemoglobin Standardization Program [NGSP]) at 34 and 102 mmol/mol levels (5.3 and 11.5% NGSP) and a bias of −0.1 mmol/mol (−0.01% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP), but with a significant slope as compared to target values. This results in a bias of −1.0 and 0.9 mmol/mol (−2.0 and 0.9% NGSP) at the 30 and 70 mmol/mol (4.9 and 8.6% NGSP) concentration level. Simulation of participation in the IFCC certification programme results in a Silver score (bias −0.1 mmol/mol, CV 1.1%). Interference in the presence of the most important Hb variants (AS, AC, AE, AD) and elevated HbA2 and HbF concentrations is less than 3 mmol/mol (0.3% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP). Conclusions Analytical performance of the HA-8190V is very good, especially with respect to precision and HbA1c quantification in the presence of the most common Hb variants.

Precision and accuracy of commercial assays for vancomycin therapeutic drug monitoring: evaluation based on external quality assessment scheme

2020 ◽  
Author(s):  
Chao-Yang Chen ◽  
Meng-Ya Li ◽  
Ling-Yun Ma ◽  
Xing-Yu Zhai ◽  
Dao-Huang Luo ◽  
...  
Keyword(s):  
Serum Concentration ◽  
Quality Assessment ◽  
Bacterial Infections ◽  
External Quality Assessment ◽  
Detection Methods ◽  
Therapeutic Drug ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
Percentage Difference ◽  
Precision And Accuracy

Abstract Background Vancomycin remains a mainstay of the treatment of Gram-positive bacterial infections. It is crucial to accurately determine vancomycin serum concentration for adequate dose adjustment. Objectives To evaluate the precision and accuracy of commercial assay techniques for vancomycin concentration and to assess the comparability of vancomycin detection methods in Chinese laboratories. Methods Human serum samples spiked with known concentrations of vancomycin were provided to laboratories participating in the external quality assessment scheme (EQAS). Assay methods included chemiluminescence, enzyme immunoassay (EIA) and so on. The dispersion of the measurements was analysed and the robust coefficient of variation (rCV), relative percentage difference (RPD) and satisfactory rate for method groups were calculated. Moreover, performance of the Chinese laboratories was assessed. Results A total of 657 results from 75 laboratories were collected, including 84 samples from 10 Chinese laboratories. The median rCV, median RPD and satisfactory rates classified by methods ranged from 1.85% to 15.87%, −14.75% to 13.34% and 94.59% to 100.00%, respectively. Significant differences were seen in precision, between kinetic interaction of microparticles in solution (KIMS) and other methods, and in accuracy, between enzyme-multiplied immunoassay technique (EMIT), fluorescence polarization immunoassay (FPIA) and other techniques. Vancomycin detection in China mainly depended on the chemiluminescence and EMIT methods, which tended to result in lower measurements. Conclusions Although almost all assays in this study achieved an acceptable performance for vancomycin serum concentration monitoring, obvious inconsistencies between methods were still observed. Chinese laboratories were more likely to underestimate vancomycin concentrations. Thus, recognizing inconsistencies between methods and regular participation in vancomycin EQAS are essential.

ORALVEQ: External quality assessment scheme of drugs of abuse in oral fluid

2008 ◽  
Vol 182 (1-3) ◽  
pp. 35-40 ◽  
Author(s):  
M. Ventura ◽  
R. Ventura ◽  
S. Pichini ◽  
S. Leal ◽  
P. Zuccaro ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Oral Fluid ◽  
Drugs Of Abuse ◽  
External Quality Assessment ◽  
External Quality ◽  
External Quality Assessment Scheme
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